Sorry, five ethical approaches, not six.

Anyways, my other note about this is that it relates more to the secular issue of age of consent than to the spiritual issue of loving primary relationship. In terms of that, I equate being fully sexually self-starting, with determination and awareness, to having the capacity to consent. In fact, the word 'consent' isn't even truly applicable in this situation, since it implies response to an external suggestion. It's more an attempt to solicit consent than an consenting action per se.

One could go further to speculate about spiritual bonding and so on, but to me, this whole topic is an angels-dancing-on-pins topic far from reality, and I don't know what use there would be to imagine how a relationship with a prepubescent could sufficiently approximate a marriage.

Most historical marriages with prepubescents (including girls) have been ethically aggressive, such as parentally arranged marriages.